Oxyacetylene and similar heating burner



May 9, 1933. A. STEPHENSON i 1,907,604

OXYACETYLENE AND SIMILAR HEATING BURNER Filed Dot. 9, 1950 4Sheets-Sheet l I@ f ff MN y@ M May 9, 1933. A. STEPHENSON 1,907,604

OXYACETYLENE AND SIMILAR HEATING BURNER Filed Oct. 9, 1930 4Sheets-Sheet 2 es I May 9, 1933. A. sTEPHENsoN 1,907,604

OXYACETYLENE AND SIMILAR HEATING BURNER Filed Oct. 9, 1930 4Sheets-Sheet 3 May 9, 1933;

A. sTEPHENsoN OXYACETYLENE AND SIMILAR HEATING BURNER Filed Oct. 9, 19304 Sheets-Sheet 4 @W BW )Mm THW Patented May 9, 1933 UNITED .STATESMTENToi-Ficavv ARTHUR STEPHENSON, F VICTORIA STATIQN HOUSE, WESTMINSTER,ENGLAND, ASSIGNOR T0 ALLENLIVERSIDGE LIMITED, OF WESTMINSTER, ENGLANDOXYACETYLENE AND SIMILAR HEATING BURNER Application led October 9, 1930,Serial No. 487,474, and in Great Britain November 26, 1929.

This invention relates to Oxy-acetylene and similar heating burners andhas particular reference to large blow-pipes employed for the localheating of metal plates, shafts and other metal objects. The presentimprovements many however be employed in conjunction With blow-pipes ofordinary size intended for welding or in conjunction with oxyacetyleneor similar burners for other uses, such as for heating refractory bodiesfor the purpose of illumination.

In blow-pipes or burners of the Oxy-acetylene and similar type asheretofore constructed, it has been customary to provide amixing devicecomprising a mixing chamber the bore of which is axially in line withthe supply conduit of one of the gases, i. e., the combustible gasWhichv may, for example, be acetylene or hydrogen, or the combustionsupporting gas, which may be oxygen or air. The gas that is conveyed bythe said supply conduit is -under substantial pressure and the other gasmay be under a smaller pressure (in Which case an injector action isobtained), or it may be under substantially the same pressure as thefirst mentioned gas, in which case each gas tends to persist in its pathof movement. In both constructions however intimate mingling oradmixture of the gases is prevented or retarded owing to the face thatthe gas passing from the supply conduit in line axially with the bore ofthe mixing chamber is in the form of a jet travelling at high velocityand forms a core or central portion of undiluted gas which is notreadily penetrated by the other gas. This core of gas is surrounded bylayers of gases mixed in different proportions some of which are moreexplosive than the Working mixture and this conduces to blow-back of theflame which may reach the supply conduit of the combustible gas with theattendant danger of explosion.

According to one feature of the present invention the mixing device hasa conduit for one of the gases, which instead of terminating in linewith the bore of the mixing chamber as heretofore, is so constructed asto cause the gas to pass across the path ofmovement of the other gas onits Way to the said noz zle and in this manner the two gases, which aresupplied under substantial pres- K sure, arercaused to become intimatelymixed Without the formation of the core or central portion of undilutedgas as mentioned above; thus the liability of blow-back of the flame isminimized. For this purpose there may be provided in the rear part 'ofthe mixing chamber a plug having an axial hole which is supplied withone of the gases, for example oxygen, and the front end of this plug isdisposed a short distance behind a shoulder in the mixing chamber so asto leave a small space between these parts for the passage of the othergas and the said front end is soformed as to cause the first-mentionedgas to pass across the said space and thereby become intimately mixedWith the other gas flowing through this space.

Another feature of the present invention relates to a burner blockhaving several burner orifices, transverse to the longitudinal axis ofthe block, for the exit of the gas so as to produce a correspondingnumber of separate flames. In one type of such burner block the burnerorifices have been formed in separate nipples fitted to the block. Thisconstruction is expensive and presents practical difficulties inmanufacture due to the fact that the independent nipples have to befixed to the block by screwing, brazing, Welding or similar methods butit has the advantage that the circulation of air around the nippleskeeps them cool Which, as is Well understood, is anecessary condition toavoid melting of the metal and back-firing of the flames. In anothertype the burner block is constructed on the monoblock principle (i. e.the block is made in a single piece with the burner orifices formedtherein) and the necessary cooling is effected by Water which is causedto circulate through the block. This construction has the advantage ofbeing cheap and easy to manufacture but the Water cooling is not soefficient as the air cooling and it necessitates additional hoseconnections to the blovvpipe for supplying and taking away this portionof the present invention is to Cil devise a construction of burner blockwhich will give the advantages of the two types referred to abovewithout the corresponding disadvantages.

According to this feature of the present invention the burner block ismade in a single piece as above mentioned with the burner oriiicesformed therein and the portions of the block containing these oriiicesare separated from each other by air gaps or slots formed in the blocksothat in effect each burner orifice is constituted by a separate aircooled nipple which is, however, integral with the main portion of theblock. Thus each burner portion is separately cooled by the current ofair induced around it and a portion of the air is also induced into thebase of each iiame which, as is well known, causes the flame to burn aslight distance away from the outer surface of the burner por tion andthereby assists the cooling action.

In order that the said invention may bel clearly understood and readilycarried into eEect, the same will now be described more fully withreference to the accompanying drawings, in which Figure 1 is an axialsection showing a blowpipe provided with one constructional form ofmixing device according to the present invention and with a tip ofordinary construction,

Figures 2, 3, 4 and 5 are axial sections showing alternativeconstructional forms of mixing devices according to the presentinvention,

Figure 6 is a transverse section taken on the line 6, 6, of Figure 5,

Figure 7 is an axial section showing a modified construction of the plugforming part of the mixing device,

Figure 8 is a front elevation of Figure 7,

Figure 9 is an enlarged sectional view of the screw threads showninFigure 7,

Figures 10 and 11 are views similar to Figures 5 and 6 showing anotherform of the mixing device, Figure 11 being a transverse section taken oniie line 11, l1 of Figure 10 and viewed from the left,

Figure 12 is an axial section showing still another form of mixingdevice,

Figure 13 is a side elevation of the plug shown in Figure 12,

Figures 14 and l5 are views similar to Figures l0 and 11 showing amodified construction, Figure 15 being a section on the line 15, 15 ofFigure 14,

Figur 16 and 17 areviews similar to Figures 14 and 15 showing stillanother construction, Figure 17 being a section taken on the line 17, 17of Figure 16,

Figure 18 is a side elevation showing a construction of plug extensionsomewhat different from that of Figure 16, 1

Figure 19 is a section showing one form of the tip,

Figure 20 is an end view of Figure 19,

Figures 2l and 22 are views similar to Figures 19 and 20 showing analternative form of the tip,

Figures 23 and 24 are also views similar to Figures 19 and 20 showinganother form of the tip,

Figure 25 is an axial section of a form of mixing device according tothe present invention constructed ,for the supply of a third 2215 Figure26 is a vertical axial section showing a form of burner block accordingto the present invention,

Figures 27, 28 and 29 are respectively a plan, a front elevation and arear elevation of Figure 26,

Figure 30 is a side elevation showing another form of burner blockaccording to the presentl invention, and f Figures 31, 32 and 33 arerespectively a plan, a front elevation and a rear elevation of Figure30.

In Figures 1 to 25 A is the mixing chamber the bore of whichcommunicates with the tip A1 by means of a pipe A2 (Figure 1) whichconveys the mixed gases to the tip, and B is the plug which4 is insertedinto the rear end of the mixing chamber and which has an 1axial hole B1for the supply of one of the gases (preferably oxygen) to the mixingchamber, the other (e. g. acetylene) being supplied by a conduit A3formed laterally in the mixing chamber. The said mixing chamber and thesaid'plug constitute the mixing device. x

Referring more particularly to Figure l, the front end of the plug B isformed with a truncated. conical portion arranged a short distancebehind a coned shoulder provided in the mixing chamber A so as to leavea small space between these parts. The front end of the plug is formedwith small holes b which are arranged atan angle to the axis of the plugand which at their outer ends terminate on the truncated conical portionof the plug, whilst their inner ends communicate with the axial supplyhole B1 of the plug. The said small holes b are arranged substantiallyat right angles to the truncated conical surface so that the gas issuingin jets from these. holes passes across the space between the truncatedconical portion of the plug and the coned shoulder of the mixingchamber. This space is supplied with the other gas which passes theretothrough an annular passage A4 provided between the vfront part of theplug and the portion of the mixing chamber in which it is disposed. Itwill be understood that there is no central hole in the front portion ofthe plug so that there can be no formation of a core or central portionof undiluted gas as in the constructions heretofore proposed.

The construction according to Figure 2 is arranged tangentially.

similar to that according to Figure 1 except that two series of smallholes b are provided at different radial distances fromthe axis of theplug and the annular passage A4 is prolonged and made narrow so as togive a restrict-ed passage for the gas. This restricted passageprovidesa safeguard against a flame Vpassing back into the supply conduit andreceptacle for the combustible gas in the unlikely event of ay blow-backoccurring despite the intimate mixture of the gases provided by thisinvention.

The constructions according to Figures 3 to 6 are similar to thataccording to Figure 2 except that instead of the truncated conicalconstruction at the front end of the plug B there are a number of stepson to which the outer ends of the small holes b2 open. In Figure 3 thecontiguous portion of the mixing chamber is coned as in Figures 1 and 2and the small holes b are arranged radially. In the constructionaccording to Figure 4 the small holes are also arranged radially butinstead of the contiguous portion of the mixing chamber being conical asin Figure 3 it is stepped to correspond with the steps on the plug B andwith a suitable space between them. The construction according toFigures 5 and 6 is similar to that of Figure 4 with the exception thatthe small holes b are lIn all these constructions according to Figures 3to 6 the oxygen issuing in jets from the small holes b pass acrossV thecombustible gas flowing between the front end of the plug and thecontiguous portion of the mixing chamber and intimate mixture is therebysecured. In the construc-,

tion according to Figures 7 to 9 a similar result is obtained byproviding the front end of the plug B with a small plug B) having a headb* with a gap between its inner surface and the front surface of theplug B. The oxygen issues through this gap and impinges upon thecombustible gas as aforesaid. The oxygen reaches the gap through apassage provided betweenthe screw threads connecting the two plugstogether, these screw threads being deliberately made badly fitting forthis purpose as shown in Figure 9.

Figures 10-and 11 show a modified construction in which instead of thelong and narrow annular passage A4 of Figures 2 to 6 a spiral passage isprovided by formi-ng the outer surface of the plug B with a. screwthread or with multiple screw threads the peripheral portions of whichfit tightly within a plain cylindrical bore formed in the rear portionof the mixing chamber. The combustible gas passes through the channelsprovided between the threads and the said bore and issues with awhirling motion across the jets of the oxygen. The said channels Iprevent the flame of a possible blowback from reaching the supplyconduit of the combustible gas. A similar result is obtained in the inwhich the screw threaded plug B fits in animperfect manner in screwthreads in the rear portion of the mixing chamber so, as to providerestricted passages for the combustible gas. This result is achieved byremoving the outer surface of the screw threads on the plug and in thechamber, the arrangement in this respect being similar to that ofFigures 7 to 9. In the two constructions according to Figures 10 to 13the small holes b are arranged as shown in Figure 1 but they may ifdesired be arranged as in any of the constructions according to Figures2 to 6.

In any of the constructions hereinbefore described the plug can beprovided with a forward extension disposed within the bore of the mixingchamber as shown in Figures 14 to 18 in which B2 represents the saidextension. This extensionbreaks up any vortex in the delivery pipe,gives a greater velocity to the mixed gases and retards back-fire fromthe tip. In the construction according to Figures 14 and l5 thisextension is in the form of a plain cylindrical part so as to leaveanannular space between it and t-hc bore. In the constructions accordingto Figures 16 and 17 the extension is formed with longitudinal straightflutes, whilst in the construction according to Figure 18 the extensionis fluted with spiral grooves or screw threads. When flutes are providedthe bore in which the extension is disposed may be similarly fluted orit may be left plain.

In the constructions according to Figures 19 to 24 the extension B2 isshown as being carried up to a tip of the blow-pipe, in which case thetip may be arranged axially in line with the mixing chamber A. InFigures 19 and 20 the extension is fluted, Figures 21 and 22 show theextension as being plain, Whilst in Figures 23 and 24 the front end ofthe extension is formed with .a collar B2* having a circle of smallholes b2* this collar fitting closely in the bore of the tip. In thelatter construction the nozzle end of the tip is pro- 4 vided withadditional holes b3 to give additional flame if necessary.- The seconstructions produce diiferent forms of flame at the tip.

is made hollow to provide for the supply of oxygen (or combustible gas)from the conduit B1 for use when the blowpipe is being employed forheating purposes and this gas passes through small holes b in a similarman- In the construction shown by vFigure 25- ner-'to/ that previouslydescribed so as to be- Nc'ome 1ntimately mixed With the other gas psupplied from the conduit A3. Any of the 'previously describedarrangement-s of the 5 small holes or forms of plug may be employed. Thepipe B1* can also be used for /P the supply of air, nitrogen, acetylene,hydrogen (or other gas) or Water according to the conditions of Work. Itwill of course be understood that in this modification When theblow-pipe is intended for heating purposes the supply of oxygen or othergas to the pipe B1X is shut off, the latter supply being brought intooperation only when it is re-' f orifices communicate With asupply-conduit C3 formed in the block and this conduit may becylindrical as shown in Figures 30 to 33, or it may be tapered as shownin Figures 26 to E29 so as to reduce the area of the conduit towards theouter or distant end thereof. This tapering formation is to maintain theflow of gas to all the flames at a uniform velocity which considerablydiminishes the tendency for the flames to become smaller to- Wards theouter or distant end of the burner block and consequently reduces thedanger of the back-firing Which is mainly due to reduced velocity of thegas. Instead of the said tapered formation the conduit may be stepped inorder to obtain a similar result. The most convenient Way of forming theaforesaid air slots C2, unless the burner block is of such a size as topermit of their being formed in the casting, is by milling to a suitabledepth. Another method which gives slightly improved results and has theadvantage of providing a uniform thickness of metal round each orificeis to form or machine the burner portions CX so that they have acircular cross section, using each orifice as the centre. Theseconstructions ensure more perfect alignment of the multiple orificesthan it is possible to obtain conveniently by any of the existingmethods of fixing the separa-te nipples into the main block. Alignmentis a very important factor in blow-pipe burners of this type, especiallyWhere theyv are intended for continuous heating under mechanicalcontrol.. The burner portions U* y ,may be arranged rwith their orificesin a single plane containing the longitudinal axis of the burner blockas shown in Figures 26 to 29 and in this construction the part of theblock on the side carrying the burner portions may be made tapered andthe part on the opposite side may also be made tapered so as to give theblock a cross-sectional shape of hexagonal form. In the constructionshown by Figures 30 to 33 the burner portions C are arrangedwith theirorifices lying in two planes at a small angle (30 for example) to oneanother. In this construction, which is primarily intended for heatingshafts and other circular objects, the burner portions C* may haveparallel sides as shown and the aforesaid air gaps or slots may extendto, or nearly to, the main part of the block from which the saidportions project. The burner portions may, if desired, be arranged With'their orifices lying in more than tWo planes.

rlfhese constructions of burner block are particularly, but notnecessarily, intended for use with a blow-pipe having any of the formsof mixing device hereinbefore described.

What I claim and desire to secure by Letters Patent of the United Statesis l.v In an Oxy-acetylene or similar heating burner having a tip, thecombination With a mixing chamber having a bore therein, of a shoulderin said mixing chamber, a plug having a substantially conical portiondisposed a short distance behind said shoulder so as to leave a smallspace for the passage of one of the gases therethrough, means forsupplying said gas to said space, a passage i'n said plug for the supplyof the other gas and means at the substantially conical portion of saidplug for causing the last mentioned gas to pass across the space betweenit and the shoulder in the mixing chamber and thereby become intimatelymixed With the gas flowing through this space.

2. In an Oxy-acetylene or similar heating burner, the combination with amixing chamber, of a frusto-conical shoulder .in said mixing chamber, aplug having a substantially conical portion which is arranged a shortdistance behind said frusto-conical shoulder so as to leave a smallspace for the passage of one of the gasesv therethrough, means forsupplying said gas to said space, a passage in said plug for the supplyof the other gas and small holes arranged in said conical portion of theplug at an angle to the axis of the plug, these small holes at theirouter ends terminati ng on the said conical portion Whilst their innerends communicate With the supply passage in said plug.

In an Oxy-acetylene or similar heating burner, the combination with amixing chamber, of a frusto-conical shoulder in said mixing chamber, aplug havfng a substantially conical formation which is arranged a shortdistance behind said frusto-conical shoulder so as to leave a smallspace for the passage of yplying sai small holes arranged substantially-at right angles to the surface" of the conical portion of the plug,these small holes at their outer ends terminating on the said conicalportion whilst their inner ends communicate wlth the supply passage insaid plug.

4. In an Oxy-acetylene or similar heating burner, the combination with amixing chamber, of a frusto-conical shoulder in said mixing chamber, aplug having a substantially conical formation which is arranged a shortdistance behind said frusto-conical shoulder so as to leave a smallspace for the passage of one of the ases therethrough, means for supgasto said space, a passage in said plug for the supply of the other gasand a series of small holes arranged substantially at right angles tothe surface of said conical portion of said plug, these small holes attheir outer ends terminating on the said conical portion whilst theirinner ends communicate with the supply passage in said plug.

5. In an Oxy-acetylene or similar heating burner, the combination withthe elements claimed in claim 1, of means giving a long restrictedpassage between the outer surface of the plug and the inner surface ofthe mixing chamber for the iow of the combustible.

gas.

6. In an Oxy-acetylene or similar heating burner, the combination withthe elements claimed in claim 1, of a screw thread formed A on the outersurface of the plug, the peripheral portions of said screw threadfitting tightly within a plain cylindrical bore in the rear portion ofthe mixing chamber so as to provide a passage of spiral formation forthe flow of the combustible gas.

7. In an Oxy-acetylene or similar heating burner, the' combination withthe elements claimed in claim 1, of a forward extension of the plug,this extension being disposed within the bore. of the mixing chamber.

8. In an Oxy-acetylene or similar heating burner, the combination with,the elements claimed vin claim 1, of a plain forward extension of the.yplug, this extension being disposed within the bore of the mixingchamber.

9. In an Oxy-acetylene orA similar heating burner, the combination withthe elements claimed in claim 1, of a longitudinally fluted forwardextension of the plug, this extension being disposed within the bore ofthe mixing chamber.

10. In an Oxy-acetylene or similar heating burner, the combination withthe ele- 12. In an Oxy-acetylene or similar heating burner, thecombination with the elements claimed in claim 1, of a forward extensionof the plug, this extension being carried up to the tip of the burner,and a collar at the front end of said extension, this collar ttingclosely in the bore of the tip and being provided with a series of smallholes passing therethrough.

13. 1n an Oxy-acetylene or similar heating burner, the combination withthe elements claimed in claim 1, of means for supplying a third gas or aliquid to the burner.

14. In an Oxy-acetylene or similar heating burner, the combination withthe elements claimed in claim 1, of a pipe disposed within the plug forthe supply of a third gas or a liquid.

15. In an Oxy-acetylene or similar heating burner, the combination withthe elements claimed in claim 1, of a helical conduit for the passage ofgas formed between said plug andsaid bore.

ARTHUR STEPHENSON.

ments claimed in claim 1, of a spirally fluted forward extension of theplug, this extension being disposed within the bore of the mixingchamber.

11. In an Oxy-acetylene orrsimilar heating burner, the combination 'withthe elements claimed in claim-1, of a forward extension of the plug,this extension being carried up to the tip of the burner.

